Baseline demographic and clinical characteristics of patients with cystic fibrosis with at least one successful LCI measurement
| All subjects | Children (<18 years) | Adults | P value* | |
| n | 112 | 68 | 44 | |
| Male:female | 64:48 | 38:30 | 26:18 | 0.85 |
| Age (IQR), years | 14.7 (8.6–22.2) | 9.2 (7.2–12.1) | 24.5 (21.6–29.3) | |
| Mean FEV1 % (SD) | 85.3 (16.0) (n=110) | 87.6 (14.4) | 81.7 (18.8) | 0.054 |
| Mean FEV1 z-score (SD) | −1.2 (1.3) | −1.0 (1.1) | −1.5 (1.4) | 0.044 |
| Mean FVC z-score | −0.6 (1.1) | −0.5 (1.0) | −0.8 (1.2) | 0.107 |
| Mean FEF25–75 z-score | −1.2 (1.5) | −0.9 (1.5) | −1.6 (1.4) | 0.018 |
| Median BMI (IQR), kg/m2 | z-score: 0.30 (−0.52 to 1.05) | 23.2 (21.2–26.5) | n/a | |
| Phe508del homozygotes, n (%) | 50 (45) | 39 (57) | 11 (25) | 0.0009 |
| Median sweat chloride, mmol/L (IQR) | 99 (85–108) (n=66) | 100 (86–110) (n=51) | 87 (71–98) (n=15) | 0.056 |
| Median age at diagnosis (IQR) | 1.0 (0.1–5.3) | 0.2 (0–1.5) | 5.0 (1.5–16.5) | <0.0001 |
| Pancreatic sufficient, n (%) | 40 (36) | 13 (19) | 27 (61) | 0.0001 |
| Never Pseudomonas aeruginosa, n (%) | 45 (40) | 24 (35) | 21 (48) | 0.237 |
| Previous Pseudomonas aeruginosa, n (%) | 17 (15) | 13 (19) | 4 (9) | 0.184 |
| Intermittent Pseudomonas aeruginosa, n (%) | 47 (42) | 30 (44) | 17 (39) | 0.695 |
| Chronic Pseudomonas aeruginosa, n (%) | 3 (3) | 1 (2) | 2 (5) | 0.560 |
| Intermittent and chronic Staphylococcus aureus, n (%) | 57 (51) | 31 (46) | 26 (59) | 0.180 |
| Intermittent and chronic Aspergillus, n (%) | 19 (17) | 11 (16) | 8 (18) | 0.801 |
| Asthma, n (%) | 19 (17) | 14 (21) | 5 (11) | 0.303 |
| Diabetes, n (%) | 3 (3) | 0 (0) | 3 (7) | n/a |
| Median (IQR) LCI | 7.7 (6.7–8.9) | 7.6 (6.8–8.6) | 7.8 (6.5–9.3) | 0.973 |
| Median (IQR) CoV LCI | 3.9 (2.6–6.1) | 3.8 (2.8–6.1) | 4.3 (2.8–6.0) | 0.710 |
| Median (IQR) CoV FRC | 4.7 (2.9–7.4) | 4.7 (3.1–7.7) | 4.9 (2.7–6.8) | 0.551 |
| Number of visits with LCI, median (IQR) | 8 (4–9) | 6 (4–7) | 10 (4–13) | 0.007 |
| Test time (min), median (IQR) | 18.9 (15.5–22.5) | 16.3 (13.5–19.3) | 21.2 (18.6–24.3) | <0.0001 |
Data are shown as mean and SD if normally distributed, otherwise as median and IQR.
Data are also shown for paediatric and adult populations separately.
Pseudomonas status relates to that at study entry and includes patients whose status was reclassified following consent based on ongoing microbiology.
Bold values indicate statistical significance.
*P value relates to comparison of adult and paediatric values and is derived from unpaired t-test for normally distributed data, Mann-Whitney U test or two-tailed Fisher’s exact test for proportions.
BMI, body mass index; CoV, coefficient of variation; FEF25–75, mid-expiratory flow; FRC, functional residual capacity; LCI, lung clearance index; n/a, not applicable.